Artificial abrasion teeth



April 3, 1956 R. sTRAcK 2,740,I99

ARTIFICIAL ABRASION TEETH Filed Feb. 14, 1952 LL/Sw una@ sat-es Patent 2,740,199 Y u anrmrcrar AnnAsIoN TEirrHV Rainer Strack, Tubingen, vGermany isi-praatten February ki4, 1952, senat N .271,509 Claims priority, application Germany"Februaryl 14, 1951 e claims. (ci. :sz-2) The present invention relates to artificial teeth and is especially directed to a novel and particularly advan- K 2,740,199 n Patented npr.` 3, 195e ice cm. long. An arrangement of this kind is character# ized essentially by :the'featu're'that the central perpendiculars erected on theindividual teeth intersect one another at a place positioned above the chewing plane at a radial distance from the individual teeth of labout 10 cm.

But all of these aforesaid types 'and arrangements of artificial teeth do not insure in a completely 'satisfactory Y way the natural performance of the chewing processand tageous group or set of artificial abrasion teeth consisting of porcelain, artificial material or the like.

The artificial molar teeth which have been manufactured and employed so far, can be subdividedregarding their shape into three fundamentally different types of teeth, viz` teeth provided with humpLlike projections, abrasion teeth and coupling teeth. v

' The teeth provided with hump-like projections'attempt to imitate the shape of the tcetho'f a natural youthful set of teeth.

The teeth which I am particularlyrefer- .e

ring to, are those which are `manufactured'in conformity with the anatomical form of the teeth. kIt was,`however, found out soon that in the Setof-teeth of older ypeople these youthful forms of teeth are altered by abrasion, and that an artificial set of teeth provided with these youthful forms of teeth is hindered in the satisfactory performance of its functions by the high, humplike projections of the teeth, which cause disadvantageous lever effects and which interfere with the natural movements of the jaws. That is why it has beentried to devise more satisfactory forms of teeth and why teeth provided with hump-like protections have been almost completely abandoned and replaced by various forms of abrasion teeth, without obtaining, however, in this way the sought for truly satisfactory result-s.

Abrasion teeth are formed without hump-like projections and provided merely with recesses and some remaining edges in their otherwise plane surfaces.

Coupling teeth are of more or less ball-like formation for the upper jaw and of correspondingly cap-like shape for the lower jaw, or vice versa. It was expected that by means of a plural-ity of cooperating pairs of teeth like this, arranged in the upper and lower jaw of an artificial set, satisfactory grinding effects would be produced. But experience has taught that the result obtained with teeth of this type is likewise not entirely satisfactory.

The principal reason for this is that the result to be obtained depends not only on the shape of the teeth as such, but also on the way in which the teeth are arranged in the artificial set, that is to say, the way in which the surfaces of the teeth are positioned in the group or set of teeth. in this respect it has so far been the custom to arrange the teeth in a plane in such a way that the central perpendiculars erected on every individual tooth extend parallel to each other and do not intersect one another either above or below the row of teeth. Moreover, the individual teeth of the known types of teeth are so shaped at their surface that they will perform, when arranged in the set, their intended function only in the plane in which they are arranged.

it has further already been proposed to form the surfaces of the teeth in such a way and to arrange the teeth in such a manner that the groups or sets of teeth constitute a sector of a spherical surface whose center is positioned approximately in the middle between the sockets of the eyes and whose spherical radius is about for .that reason do not produce the required maximum of chewing effects. e

Elaborate examinationv of voluminous morphologic material and cinematic examination ofthe chewing movements-of the 'lower`jaw, Aas a result of and in conformity with vthe formation of the chewing surfacesand the individual muscular strength and exertion, have taught that the surfaces of abraded natural teeth always follow the course of a curved and twisted surface. It is obvious, therefore, that only when such curved or twisted chewing surfaces are provided also in the articial sets, natural chewing movements of the lower jaw and `a maximum of chewing effects can be obtained, and that onlyin this way injurious activities of theA joint of'the jaw can `be prevented, which at an advanced age will not adapt itself tonew ways of motion.

That is 'why the artificial groups and sets of abrasion teeth produced 'from porcelain, ar ticial` material or the like in'conformity with the herein disclosed invention, are so devised and arranged that the central perpendiculars erected on the chewing surfaces of the bicuspid teeth intersect one another at a place below the chewing sur# face, and that the central perpendiculars erected onthe chewing surfaces of the rear molar teeth intersect one another'at a place above the chewing surface, while the contrai perpendiculars erected on the molar teeth posi` tioned between the two first mentioned groups of teeth extend parallel to one another;v

With this object in View, the present invention mainly consists in a denture comprising at least one row of false teeth composed of at least one rear molar tooth located at one end of the row of false teeth, of at least one bicuspid tooth located at the other end of therow of false teeth, and of at least one intermediate tooth located intermediate the rear molar tooth and the bicuspid tooth, the false teeth having chewing surfaces forming along the row of false teeth a continuous twisted masticating surface, the chewing surface of the rear molar tooth being inwardly and downwardly inclined with respect to the chew ing surface of the intermediate tooth, and the chewing surface of the bicuspid tooth being outwardly and downwardly inclined with respect to the intermediate tooth.

The drawing is a View of a group of molar teeth' arranged in such a way that their chewing surfaces are following the course of a curved and twisted surface.

Referring now mo-re particularly to the drawing, which shows the new form of construction in which the bicuspid teeth 10, and the molar teeth 1l, 12 are so arranged in the curved backing 13 that the chewing surfaces of the teeth 10, 11, 12 follow the course of a curved and twisted surface. The construction shown is, therefore, characterized by the feature that the central perpendiculars 14 erected on the chewing surfaces of the teeth 10 arranged in the forward area of the arc of the teeth intersect one another at a place positioned below the chewing surface so that the kchewing surfaces of the two bicuspids 10 are outwardly and downwardly inclined, and that the central perpendiculars 15 erected on the chewing surfaces of the rear teeth 11 intersect one another at a place positioned above the chewing surface so that the chewing surfaces of the rear molars 11 are inwardly and downwardly inclined, while the central per pendiculars 16 erected on the teeth 12 positioned between the two groups of teeth 10 and 11 to extend parallel to,

so that the chewing surface of the foremost molar 12 is substantially horizontal. In a construction like this the individual -teeth are so shaped and so arranged in groups in the arc of the set that the chewing surfaces are con tinued smoothly and uniformly by the adjacent chewing surfaces so that all chewing surfaces form a twisted surface.

It would be impossible toy arrange the customary kind of artificial teeth in a curved and twisted surface of the type described, as any attempt of this kind would produce in the chewing surface of the plurality of teeth step-like sections. This is particularly true of the teeth provided with hump-like projections and of the aforesaid coupling teeth, but also applies to the hitherto known forms of abrasion teeth, considering that also the latter type of teeth are not modelled in conformity with the course of the curved and twisted surface.

What l claim as new and desire to secure by Letters Patent of the United States is: l

1. In a denture, in combination, at least one row of false teeth composed of at least one rear molar tooth located at one end of said row of false teeth, of at least one bicuspid tooth located at the other end of said row of false teeth, and of at least one intermediate tooth located intermediate said rear molar tooth and said bicuspid tooth, said false teeth having chewing surfaces forming along said row of false teeth a continuous twisted masticating surface, the chewing surface of said rear molar tooth being inwardly and downwardly inclined with respect to the chewing surface of said intermediate tooth, and the chewing surface of said bicuspid tooth being outwardly and downwardly inclined with respect to said intermediate tooth.

2. ln a denture, in combination, a row of false teeth composed of at least one rear molar tooth located at one end of said row of false teeth, of two bicuspid teeth located at the other end of said row of false teeth, and of one molar tooth located intermediate said rear molar tooth and said bicuspid teeth, said false teeth having chewing surfaces forming together along said row of false teeth a continuous twisted masticating surface, the chewing surface of said rear molar tooth being inwardly and downwardly inclined with respect to the chewing surface of said one molar tooth, and the chewing surfaces of said bicuspid teeth being outwardly and downwardly inclined with respect to said one molar tooth. Y

3. In an upper denture, in combination, at least one row of false teeth having inner, outer and chewing surfaces, said row of false teeth being composed of at least one rear molar tooth located at one end of said row of false teeth, of at least one bicuspid tooth located at the other end -of said row of false teeth, and of at least one intermediate tooth located intermediate said rear molar tooth and said bicuspid tooth, said chewing surfaces forming along said row of false teeth a continuous twisted masticating surface, the chewing surface of said rear molar tooth sloping toward said outer surface of the same and the chewing surface of ,said bicuspid tooth sloping toward said inner surface of the same.

4. In a lower denture, in combination, at least one row of false teeth having inner, outer and chewing surfaces, said row of false teeth being composed of at least one rear molar tooth located at one end of said row of false teeth, of at least one bicuspid tooth located at the other end of said row of false teeth, and of at least one intermediate tooth located intermediate said rear molar tooth and said bicuspid tooth, said chewing surfaces forming along said row of false teeth a continuous twisted masticating surface, the chewing surface of said rear molar tooth sloping toward said inner surfaceof the same and the chewing surface of said bicuspid tooth sloping toward said outer surface of the same.

References Cited in the tile of this patent UNITED STATES PATENTS 2,171,759 Meyer Sept. 5, 1939 

